[PATCH 4.20 030/111] r8169: dont try to read counters if chip is in a PCI power-save state

[Greg Kroah-Hartman]

4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Heiner Kallweit <hkallweit1@xxxxxxxxx>

[ Upstream commit 10262b0b53666cbc506989b17a3ead1e9c3b43b4 ]

Avoid log spam caused by trying to read counters from the chip whilst
it is in a PCI power-save state.

Reference: https://bugzilla.kernel.org/show_bug.cgi?id=107421

Fixes: 1ef7286e7f36 ("r8169: Dereference MMIO address immediately before use")
Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/realtek/r8169.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/realtek/r8169.c
+++ b/drivers/net/ethernet/realtek/r8169.c
@@ -1729,11 +1729,13 @@ static bool rtl8169_reset_counters(struc
 
 static bool rtl8169_update_counters(struct rtl8169_private *tp)
 {
+	u8 val = RTL_R8(tp, ChipCmd);
+
 	/*
 	 * Some chips are unable to dump tally counters when the receiver
-	 * is disabled.
+	 * is disabled. If 0xff chip may be in a PCI power-save state.
 	 */
-	if ((RTL_R8(tp, ChipCmd) & CmdRxEnb) == 0)
+	if (!(val & CmdRxEnb) || val == 0xff)
 		return true;
 
 	return rtl8169_do_counters(tp, CounterDump);